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In vitro Comparison of Anti‐Inflammatory Activity of Green Tea Catechins
Author(s) -
Fechtner Sabrina,
Ahmed Salahuddin
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.916.4
Subject(s) - catechin , chemistry , western blot , green tea extract , mtt assay , pharmacology , cyclooxygenase , in vitro , rheumatoid arthritis , epicatechin gallate , cytokine , zymography , anti inflammatory , microbiology and biotechnology , green tea , immunology , biochemistry , matrix metalloproteinase , enzyme , medicine , biology , polyphenol , food science , antioxidant , gene
Background/Purpose Green tea contains considerable amounts of epigallocatechin‐3‐gallate (EGCG), epigallocatechin (EGC), and epicatechin (EC). EGCG has already been shown to exhibit anti‐inflammatory activity. Pro‐inflammatory cytokine interleukin‐1β (IL‐1β) produced by monocytes and macrophages plays an important role in rheumatoid arthritis (RA). In this study, we compared the efficacy of different catechins in reducing the inflammatory response to IL‐1β in human RA synovial fibroblasts (RA‐FLS). Methods The effect of EGCG, EGC, and EC on RA‐FLS viability was tested using MTT assay. RA‐FLS were pre‐treated with different concentration EGCG, EGC, and EC (5–20 μM) overnight then stimulated with IL‐1β (10 ng/ml) for 24 hours. Condition media was used to quantify IL‐6 and IL‐8 production by ELISA, and MMP‐2 activity by gelatin zymography. The cellular expression of cyclooxygenase‐2 (Cox‐2) and Cox‐1 was evaluated using Western blotting method. Results EGCG, EGC, and EC exhibit no toxicity in human RA‐FLS (n=3). Among the tested catechins, EGCG was the most effective catechin at inhibiting IL‐6 and IL‐8 production by 59% and 57%, respectively (n=3; p<0.05). Western blot analysis showed that EGCG selectively inhibits Cox‐2 expression by 86% after IL‐1β stimulation (n=3; p<0.05) and had no significant effect on IL‐1β‐induced Cox‐1 expression. However, EGC not only inhibited IL‐1β‐induced Cox‐2 expression by 58%, it also reduced IL‐1β‐induced Cox‐1 expression by 20% (n=3; p<0.05). Interestingly, our gelatin zymography results showed that EGC was as effective as EGCG in reducing IL‐1β‐induced MMP‐2 activity by 85% in human RA‐FLS (n=3; p<0.05). In all the proposed assays, EC showed no anti‐inflammatory properties. Conclusion The results of the study suggest that green tea catechins differentially interfere with IL‐1β signaling pathways to regulate IL‐6 and IL‐8 production, and Cox‐2, Cox‐1, and MMP‐2 expression in human RA‐FLS. Among the catechins tested, EGCG was a more potent anti‐inflammatory compound than EGC and EC in human RA‐FLS. EGCG and EGC display moderate anti‐inflammatory properties while EC displays minimal anti‐inflammatory properties. Together, these results suggest that the gallate moiety is essential to EGCG and EGC inhibiting IL‐1β‐induced inflammatory mediators in RA. Support or Funding Information This study was supported by the Robbers Research Award (S.F.), NIH grant AR063104 (S.A.), the Arthritis Foundation Innovative Research Grant (S.A.), the start‐up funds from Washington State University (S.A.).